hex-2-enal

green aldehyde Key food odorant

Found in 6 ingredients across the CompKitchen flavor graph.

Look up another compound — search by name, CAS number, PubChem CID, or FEMA #.

Key food odorant (individualist)

Dunkel et al. 2014

Identified in the meta-analysis of 227 food samples as one of 151 individualist odorants — appears in <5% of foods, carries the diagnostic signature of specific ingredients. Characteristic odor: green, apple-like.

Source: Angew. Chem. Int. Ed. 2014, 53, 7124–7143

Properties

Odor description: green, apple, grassy, leafy
Odor threshold — orthonasal, in clean water: 17.0 ppb – 110 ppb median 63.5 ppb · 2 published values · see all 2 with sources
CAS number: 6728-26-3
Retention index: 856

Not in FEMA GRAS publications 1-33. Of 3,367 listed flavoring substances, none match this compound name. May still be food-safe under other regulatory routes (FDA 21 CFR 172, EFSA, JECFA) — check femaflavor.org for the authoritative current list.

How this molecule is described

Sources disagree about odour more often than they disagree about chemistry. Rather than show one answer, here is every description on file with how many ingredient records carry it.

Descriptions on file

Ordered by how many independent descriptor streams give each wording, then by how often it appears. The bar is still replication — one source copied onto many ingredients scores high there — so the two can disagree.

fresh FlavorDB 2.0

green FlavorDB 2.0

green, apple, grassy, leafy shown above Llm Adjudicated

—

Bars are the share of ingredient records carrying each description. High agreement means the sources replicate each other — not necessarily that they are right.

Published thresholds

2 measured values from the literature. Grouped by what was actually measured — a threshold smelled in clean water, tasted in the mouth, or measured in a real food are three different quantities and are not pooled.

Orthonasal, in clean water

17.0 ppb – 110 ppb

The reference measurement — smelled in water. OAV is computed against this.

Threshold	Matrix	Source	Paper
17.0 ppb	water_odor	Leffingwell	—
110 ppb SIDA	water	Dunkel 2014	—

Only values we can attribute are listed. Where a compendium's licence does not permit public attribution its figures are omitted here, so every number on this page traces to a citable source.

Thresholds in published tables

Numbers printed in open-access papers, grouped by the medium the table states. Median and full range of the values; “agree” means two or more papers whose middle 80% of values sit within 100×. Not reviewed.

Medium	Median	Range	Values	Papers	Papers agree?
air	25.45 µg/L air	0.0031–429	24	20	no (2.6 decades)
ethanol solution	0.284 ppb	0.284–0.284	1	1	one paper
food matrix	55 ppb	0.0031–1.8e+03	42	35	yes
oil	0.635 ppb	0.3–420	4	4	no (3.1 decades)
unstated	17 ppb	0.0031–1.7e+04	116	86	no (2.3 decades)
water	19.2 ppb	0.017–429	73	63	yes

Found in

Measured impact first, then profile share

Every ingredient known to contain hex-2-enal. Ingredients with a measured concentration come first, ranked by odour activity; the rest follow by how large a share of that ingredient's profile this molecule is. The figure beside each is how many different compounds that ingredient has in total — not the concentration of hex-2-enal in it.

288 cmpds

330 cmpds

353 cmpds

393 cmpds